Question Detail
Question
Which of the following is true about intrinsic semiconductors?
i. Each semiconductor atom undergoes paired sharing of electrons with four neighbouring atoms.
ii. Conduction is due equally to holes and electrons.
iii. Group V atoms in the semiconductor share four electrons with four neighbouring atoms with an extra electron.
iv. Band structure is between that of metals and insulators.
i. Each semiconductor atom undergoes paired sharing of electrons with four neighbouring atoms.
ii. Conduction is due equally to holes and electrons.
iii. Group V atoms in the semiconductor share four electrons with four neighbouring atoms with an extra electron.
iv. Band structure is between that of metals and insulators.
Correct Answer
Option B is the correct answer.
Detailed Explanation
Let's analyze each statement for an intrinsic semiconductor:i. True: Intrinsic semiconductors like Silicon or Germanium form covalent bonds where each atom shares four electrons with its neighbours.ii. True: In an intrinsic semiconductor, electron-hole pairs are created by thermal energy, and the number of electrons in the conduction band equals the number of holes in the valence band, leading to equal contribution to conduction.iii. False: Group V atoms are donor impurities used in n-type extrinsic semiconductors, not intrinsic ones. They donate an extra electron, they don't share four electrons with an extra electron from neighbours in this context.iv. True: Semiconductors have a band gap that is smaller than insulators but larger than metals (which may have overlapping bands or no band gap).Therefore, statements i, ii, and iv are true.
Hint
Recall the definition and properties of intrinsic semiconductors, including their atomic structure, charge carriers, and energy band model.